Failover Monitoring; Module Health Monitoring - Cisco Catalyst 6500 Series Configuration Manual

Chapter 15 Using Failover
Table 15-1 Failover Behavior (continued)
Failure Event
Failover link failed during
operation
Failover link failed at startup
State link failed
Interface failure on active
module above threshold
Interface failure on standby
module above threshold
Trunk failure in inter-switch
setup

Failover Monitoring

The FWSM monitors each module for overall health and for interface health. See the following sections
for more information about how the FWSM performs tests to determine the state of each module:
•
•

Module Health Monitoring

The FWSM determines the health of the other module by monitoring the failover link. When a module
does not receive hello messages on the failover link, then the module sends an ARP request on all
interfaces, including the failover interface. The FWSM retries a user-configurable number of times. The
action the FWSM takes depends on the response from the other module. See the following possible
actions:
•
•
OL-6392-01
Policy Active Action
No failover Mark failover
interface as failed
No failover Mark failover
interface as failed
No failover No action
Failover Mark active as
failed
No failover No action
No failover No action
Module Health Monitoring, page 15-13
Interface Monitoring, page 15-14
If the FWSM receives a response on any interface, then it does not fail over.
If the FWSM does not receive a response on any interface, then the standby module switches to
active mode and classifies the other module as failed.
Catalyst 6500 Series Switch and Cisco 7600 Series Router Firewall Services Module Configuration Guide
Standby Action Notes
Mark failover You should restore the failover
interface as failed link as soon as possible because
the module cannot fail over to the
standby module while the failover
link is down.
Become active If the failover link is down at
startup, both modules will become
active.
No action State information will become out
of date, and sessions will be
terminated if a failover occurs.
Become active None.
Mark standby as When the standby module is
failed marked as failed, then the active
module will not attempt to fail over
even if the interface failure
threshold is surpassed.
Become active Both modules become active if all
communication between the
modules is terminated, as in the
case of a trunk failure. Neither
module receives hello messages,
and both modules assume the
active role.
Understanding Failover
15-13